The number of cars sold by a car salesperson during each of the last 25 weeks is the following: What is the probability that the salesperson will sell one car during a week?
A) 0.20
B) 0.40
C) 0.60
D) 0.80

Question

The number of cars sold by a car salesperson during each of the last 25 weeks is the following:  What is the probability that the salesperson will sell one car during a week?
A) 0.20 
B) 0.40 
C) 0.60 
D) 0.80

Quizplus · Accepted Answer

Out of the last 25 weeks, the salesperson sold at least one car in 20 of those weeks. Therefore, the probability of selling at least one car in a week is 20/25 or 0.80. The complement of this event (i.e. not selling any car in a week) happened in 5 of the last 25 weeks. Therefore, the probability of selling no car in a week is 5/25 or 0.20. Since we are interested in selling at least one car in a week, the answer is (1 - 0.20) or 0.80, which corresponds to choice B.

The Number of Cars Sold by a Car Salesperson During